IBM BPM, V8.0.1, All platforms > Programming IBM BPM > Developing client applications for BPEL processes and tasks > Developing web applications using JSF components > Adding the CommandBar component to a JSF application
How commands are processed
Use the CommandBar component to add action buttons to your application. The component creates the buttons for the actions in the user interface and handles the events that are created when a button is clicked.
These buttons trigger functions that act on the objects that are returned by a com.ibm.bpe.jsf.handler.ItemProvider interface, such as the BPCListHandler class, or the BPCDetailsHandler class. The CommandBar component uses the item provider that is defined by the value of the model attribute in the bpe:commandbar tag.
When a button in the command-bar section of the application's user interface is clicked, the associated event is handled by the CommandBar component in the following way.
- The CommandBar component identifies the implementation of the com.ibm.bpc.clientcore.Command interface that is specified for the button that generated the event.
- If the model associated with the CommandBar component implements the com.ibm.bpe.jsf.handler.ErrorHandler interface, the clearErrorMap method is invoked to remove error messages from previous events.
- The getSelectedItems method of the ItemProvider interface is called. The list of items that is returned is passed to the execute method of the command, and the command is invoked.
- The CommandBar component determines the JavaServer Faces (JSF) navigation target. If an action attribute is not specified in the bpe:commandbar tag, the return value of the execute method specifies the navigation target.
If the action attribute is set to a JSF method binding, the string returned by the method is interpreted as the navigation target. The action attribute can also specify an explicit navigation target.